Hypotension Prediction Index for Prevention of Hypotension during Moderate- to High-risk Noncardiac Surgery.

BACKGROUND: The Hypotension Prediction Index is a commercially available algorithm, based on arterial waveform features, that predicts hypotension defined as mean arterial pressure less than 65 mmHg for at least 1 min. We therefore tested the primary hypothesis that index guidance reduces the duration and severity of hypotension during noncardiac surgery. METHODS: We enrolled adults having moderate- or high-risk noncardiac surgery with invasive arterial pressure monitoring. Participating patients were randomized to hemodynamic management with or without index guidance. Clinicians caring for patients assigned to guidance were alerted when the index exceeded 85 (range, 0 to 100) and a treatment algorithm based on advanced hemodynamic parameters suggested vasopressor administration, fluid administration, inotrope administration, or observation. Primary outcome was the amount of hypotension, defined as time-weighted average mean arterial pressure less than 65 mmHg. Secondary outcomes were time-weighted mean pressures less than 60 and 55 mmHg. RESULTS: Among 214 enrolled patients, guidance was provided for 105 (49%) patients randomly assigned to the index guidance group. The median (first quartile, third quartile) time-weighted average mean arterial pressure less than 65 mmHg was 0.14 (0.03, 0.37) in guided patients versus 0.14 (0.03, 0.39) mmHg in unguided patients: median difference (95% CI) of 0 (-0.03 to 0.04), P = 0.757. Index guidance therefore did not reduce amount of hypotension less than 65 mmHg, nor did it reduce hypotension less than 60 or 55 mmHg. Post hoc, guidance was associated with less hypotension when analysis was restricted to episodes during which clinicians intervened. CONCLUSIONS: In this pilot trial, index guidance did not reduce the amount of intraoperative hypotension. Half of the alerts were not followed by treatment, presumably due to short warning time, complex treatment algorithm, or clinicians ignoring the alert. In the future we plan to use a lower index alert threshold and a simpler treatment algorithm that emphasizes prompt treatment.

The intraoperative glycemic response to intravenous insulin during noncardiac surgery: a subanalysis of the DeLiT randomized trial.

Patient characteristics may affect patients' response to insulin. We examined the impact of body weight and presence of diabetes on the response to insulin during noncardiac surgery. We studied 202 patients who were enrolled in the DeLiT Trial and received intraoperative intravenous insulin. Univariable and multivariable analyses (Bonferroni corrected) assessed the relationship between patient's response to the initial intraoperative I.V. bolus of regular insulin and the factors of interest. Blood glucose concentrations decreased 8.3 ± 10mg/dL (0.46 ± 0.56mmol/L) per unit of I.V. insulin in 30minutes. The response to insulin was similar in patients with or without diabetes (adjusted mean difference [97.5% confidence interval], 0.2 [-3.9, 4.2] mg/dL, 0.01 [-0.22, 0.24] mmol/L; P = .93). No relationship was found between insulin response and body weight (P=0.38). Our results suggest that adjustment for body weight and the presence of diabetes may not improve intraoperative insulin treatment algorithms.

Postoperative adverse effects after recent or remote lithium therapy.

Patients receiving preoperative lithium therapy for bipolar disorder may present unique challenges in the perioperative period and during critical illness. Two cases of critically ill patients who developed lithium-induced adverse reactions in the perioperative period due to the low therapeutic index are reported.

Deceased donor hyperglycemia and liver graft dysfunction.

CONTEXT: Hyperglycemia is common in deceased donors, and provokes numerous adverse events in hepatocytic mitochondria. OBJECTIVE: To determine whether hyperglycemia in deceased donors is associated with graft dysfunction after orthotopic liver transplant. METHODS: Charts on 572 liver transplants performed at the Cleveland Clinic between January 2005 and October 2010 were reviewed. The primary measure was time-weighted averages of donors' glucose measurements. Liver graft dysfunction was defined as (1) primary nonfunction as indicated by death or retransplant or (2) liver graft dysfunction as indicated by an aspartate amino transferase level greater than 2000 U/L or prothrombin time greater than 16 seconds during the first postoperative week. The relationship of interest was estimated by using a multivariable logistic regression. RESULTS: The incidence of graft dysfunction was 25%. No significant relationship was found between the range of donor glucose measurements and liver graft dysfunction after donor characteristics were adjusted for (P= .14, Wald test, adjusted odds ratio [95% CI] for liver graft dysfunction corresponding to a relative doubling in time-weighted average for donor glucose of 1.43 [0.89-2.30]). The results thus do not suggest that strict glucose control in donors is likely to improve graft quality.

Predicting immunosuppressant dosing in the early postoperative period with noninvasive indocyanine green elimination following orthotopic liver transplantation.

Twenty adult patients undergoing orthotopic liver transplantation (OLT) were enrolled in this study, with the noninvasive indocyanine green plasma disappearance rate (ICG-PDR) measured both during and after OLT to assess the relationship between ICG-PDR and the ability of patients to achieve therapeutic postoperative tacrolimus immunosuppressant blood levels. Liver function was determined at both 2 and 18 hours post reperfusion with the ICG-PDR k value (1/min). Postoperative standard serum measures of liver function as well as liver biopsies were also collected and analyzed. The median ICG-PDR k value for the study group at 2 hours post reperfusion was 0.20 (0.16, 0.27), whereas at 18 hours post reperfusion, it was 0.22 (0.18, 0.35). The median change in the k value between the two ICG-PDR measurements was 0.05 (-0.02, 0.07) with P = 0.02. There was an interaction between the postoperative day 1 (18 hours post reperfusion) ICG-PDR k value and the linear increase in the tacrolimus blood level, such that the greater the k value was, the more gradual the observed rise was in tacrolimus over time [that is, the longer it took to achieve a therapeutic blood level (>12 ng/mL), P = 0.003]. Of the 16 patients that received tacrolimus, comparable dosing on a per kilogram body weight basis was observed. Also, no significant association between ICG-PDR k values and postoperative liver biopsy results was seen. This study demonstrates that the ICG-PDR measurement is a modality with the potential to assist in achieving adequate blood levels of tacrolimus following OLT.

Hetastarch allergy and positive latex radioallergosorbent test in a patient suffering cardiovascular decompensation during multiple perioperative periods.

The cause of sudden cardiovascular collapse in the perioperative period can be elusive. Allergy may be overlooked as a cause. When allergy is considered, latex is often suspected. Because hetastarch is frequently used in situations involving hypovolemia and hypotension, and because allergic reactions to it are rare, it may be overlooked as a possible allergen. We report a case of a patient suffering cardiovascular decompensation during four nonconsecutive perioperative periods before it was determined that she was allergic to hetastarch. She also had a very highly positive latex radioallergosorbent test, suggesting a latex allergy.

The comparative hemodynamic effects of methohexital and remifentanil in electroconvulsive therapy.

Remifentanil is a short acting opioid frequently used to supplement general anesthesia for brief procedures. Narcotic agents are known for their ability to blunt autonomic responses to stimuli such as laryngoscopy and intubation and do not alter seizure threshold. We hypothesized that the combination of remifentanil and methohexital for induction would produce favorable suppression of sympathetic response during electroconvulsive therapy (ECT). With Institutional Review Board approval and informed consent, patients were enrolled in a prospective, randomized, double-blind, crossover study of methohexital alone versus remifentanil with an adjuvant of low-dose methohexital. One hundred ten ECT treatments were evaluated and subjects were treated in an alternating fashion with one of two induction protocols: Methohexital alone in an 80-100 mg IV bolus or remifentanil 500 mcg IV bolus combined with methohexital 40 mg IV. Bilateral ECT was performed in standard fashion and systolic blood pressure and heart rate were recorded throughout the procedure. No significant differences were found in baseline hemodynamic values between the two groups. Heart rate was significantly lower in the remifentanil group versus methohexital group at one minute post-induction and just prior to ECT stimulus. Pre-ECT systolic blood pressure was not significantly different between the two groups. Heart rate remained lower in the remifentanil group at all measured timepoints during the treatment and continuously for five minutes after the seizure. Systolic blood pressure was significantly lower at one minute following the end of seizure and five minutes after end of seizure. Remifentanil's short duration of action, favorable side effect profile, potential proconvulsant activity and ability to suppress hemodynamic response make it a potential novel drug for ECT induction.

A comparison of postoperative pain control in patients after right lobe donor hepatectomy and major hepatic resection for tumor.

After initiating a living donor liver transplant program at our institution, we observed that donor patients experienced significant postoperative pain despite the use of thoracic patient-controlled epidural analgesia (PCEA) infusion catheters. We retrospectively compared patients who underwent right lobe donor hepatectomy (RLDH, n = 15) with patients who had undergone major hepatic resection for tumor (MHRT, n = 15) to elucidate the cause for this observation. All patients had preoperative thoracic epidural catheters placed, and both groups had similar surgical exposure. Demographic information, intraoperative variables, intensity of postoperative pain by visual analog pain score (VAPS), side effects, total number of requested and delivered PCEA doses, and the total amount of bupivacaine (mg) and volume (mL) of PCEA solution administered through 48 h postoperatively were collected and analyzed. The RLDH group had a significantly longer surgical duration than did the MHRT group. The RLDH group patients had higher postoperative pain scores (P = 0.034), and were 2.76 (1.12-6.82, 95% CI) times more likely to have pain than those patients in the MHRT group. There was no significant difference between patient groups for the amount of bupivacaine and volume of PCEA solution administered. These observations may be explained, in part, by the longer duration of surgery in the RLDH group. The possible role of preemptive analgesia via PCEA infusion and better perioperative teaching of PCEA use are discussed; these may lead to improved early postoperative pain control in RLDH patients.

Leukocyte reduction during orthotopic liver transplantation and postoperative outcome: a pilot study.

STUDY OBJECTIVE: To investigate the effect of intraoperative leukocyte reduction of administered blood products on the incidence of acute cellular rejection and postoperative patient outcome. DESIGN: Prospective, nonrandomized, historical control study. SETTING: Academic tertiary medical center. PATIENTS: The study group (Group 1) consisted of 30 consecutive adult patients with end-stage liver disease scheduled to undergo orthotopic liver transplantation (OLT) between 1998 and 2000. The historical control group (Group 2) consisted of 30 adult patients with end-stage liver disease matched to study group patients as closely as possible for age, gender, and etiology of liver disease who underwent OLT between 1995 and 1999. INTERVENTIONS: Group 1 patients had all intraoperative allogeneic and cell salvaged blood products leukocyte reduced before administration. Group 2 patients underwent OLT without leukocyte filtration of any administered blood products. MEASUREMENTS: Demographic data were collected for both patient groups and included age, gender, etiology of liver disease, and both intraoperative and postoperative immunosuppression. Demographic allograft donor data for both patient groups were collected and included age, gender, use of vasopressors during procurement, and cold and warm donor organ ischemic times. Outcome variables measured included incidence of acute cellular rejection, length of intensive care unit (ICU) and length of hospital stay, incidence of both graft loss and retransplantation, and mortality. MAIN RESULTS: The incidence of acute cellular rejection was 40% in Group 1 and 66.7% in Group 2 (p = 0.037). Length of ICU stay was 3.0 (2.0, 5.0) days in Group 1 and 4.0 (3.0, 6.0) days in Group 2 (p = 0.16). Length of hospital stay was 14.0 (11.0, 18.0) days in Group 1 and 18.0 (14.0, 27.0) days in Group 2 (p = 0.035). One allograft was lost in Group 2 because of primary nonfunction requiring retransplantation (p = 0.31), and three postoperative deaths occurred in Group 1 as a result of multisystem organ failure (p = 0.08). CONCLUSIONS: Coincident with leukocyte reduction of all administered blood products during OLT, an improved outcome was observed in Group 1 patients as demonstrated by both a decreased incidence of acute cellular rejection and length of hospital stay.

The effect of craniotomy location on postoperative pain and nausea.

PURPOSE: At least one retrospective study has suggested that the need for postoperative control of pain and nausea depends on the location of the cranial surgery. This prospective study was performed to examine the hypothesis that patients who have had infratentorial craniotomy experience more severe pain and more frequent nausea than those with supratentorial procedures. METHODS: We compared postoperative outcomes in 28 patients with infratentorial craniotomy, 53 with supratentorial craniotomy, and 47 with complex spinal cord surgery (the control group). Anesthesia was standardized for all three groups and the concentration of isoflurane was titrated to keep mean arterial pressure within 30% of preoperative values. Severity of pain and frequency of nausea and vomiting were recorded for 24 h after surgery. Pain was assessed with a verbal pain score scale of 0-10, with 10 being the worst pain imaginable. Data were collected for 24 h postoperatively. RESULTS: Because nausea and pain diminish drastically 2 h after surgery, pairwise differences were assessed at each point within the first 2 h. Within 30 min of extubation, median pain scores in the supratentorial and spine groups rose to 2 and in the infratentorial group to 5. The statistical differences between groups were not significant ( P > 0.06) by logistic regression. Also, the incidence of nausea was not significantly different (57% supratentorial, 57% spine, 67% infratentorial; P = 0.62) by Dunn's procedure. CONCLUSION: There were no significant differences in the severity of pain or the frequency of nausea based on the craniotomy site.